Power issue

[loki365]

So when I picked out a new GPU I realised my old PSU wasn't up to scratch. I found a deal for a 750w corsair ax750 on scan and went ahead.

After sorting other issues with my build I thought I was in the clear. However, the power switch on my front I/O has become very temperamental. At first it would take a while after pressing the button for my system to power up. Now it won't respond at all.
I am totally at a loss. I didn't even touch the I/O connections when installing the new parts. Please help!

[Agent]

First point of call with an issue like this: You need to build it outside of the case. It could be a simple short somewhere.

Before that though, remove all USB / Firewire / any other cables apart from power and see if it starts then. If not, refer to the above.

[loki365]

Thanks, I'll get on to that :s

[loki365]

First point of call with an issue like this: You need to build it outside of the case. It could be a simple short somewhere.

Before that though, remove all USB / Firewire / any other cables apart from power and see if it starts then. If not, refer to the above.

Tried first step, no joy.

What am I looking for when I have the build outside?

[jim]

Sometimes the board can be shorting against part of the case, and building it outside will avoid that. Cases are metal and conductive, cardboard boxes / tables usually aren't.

The next thing to start doing is to remove as many components as possible, and see what happens. If you've got any accessories attached, remove them. Then start swapping things around. Try the old PSU, see if that works. If you've got alternative memory, try that. Or use only one stick at a time.

You need to eliminate things until it starts working, and then you can isolate which part is causing the problem. Of course though, if the problem is the CPU or the mobo then it's very difficult to isolate.

[Agent]

Under normally all circumstances, you'll get some sort of initial power up, even with faulty parts. This is why I'm thinking it's more likely a short at this point.

[loki365]

Thanks guys. About to try first batch. Wish me luck!

[loki365]

Ok, so 24 pin atx cable is connected, same with CPU cable. RAM, CPU, power switch, power led and a fan on my heat sink. Nothing. Not a sausage o.O

[Flibb]

Also worth checking its not just the power switch arsing about. Had an issue a couple of years ago with new parts in my old case, had intermittent boot issues, turned out to be that the power switch had shifted in its holder and wasn't operating properly, re-seated it and it was fine.

[loki365]

I've taken the face off of the case and I'm actuating the power switch directly. If I plugged the reset switch into the power button area would I get the desired effect. (Just as a test, not a permanent solution.)

[watercooled]

Yes the reset switch should work the same as the power switch. Alternatively, you can just bridge the header pins for the power switch with something conductive like a screwdriver.

[loki365]

Bumping with extra riddle to add.

I plugged in my old PSU (420watt cooler master M2 pro)
Turned on with no issues whatsoever.

Refund. I think.

[watercooled]

What GPU are you using?

[loki365]

R9 280x TOP edition. Don't worry, I didn't plug THAT in to the 420w PSU.

[loki365]

Had bought a 750w 80plus gold Corsair 750ax from Scan. Turned out it was factory refurbed.

[watercooled]

I was just thinking, you might be able to get away with your existing PSU in the meantime if you have to return the new one.

TBH provided enough of that 420W is available on the 12v rail, and depending on the rest of the components used in your system, you should be OK under normal load as shown here: http://www.anandtech.com/show/7400/t...at-asus-xfx/20

I'd probably be cautious with heavily loading the CPU and GPU simultaneously as you might be cutting it close though.